One of the striking aspects of Chelsea's progress to the Champions League semi-finals on Wednesday night was the demeanour of Laurent Blanc during and after Paris Saint-Germain's 2-0 defeat in the second leg at Stamford Bridge.

In the opening quarter of the match Blanc was the most visible presence on the touchline, patrolling his rectangle with a reassuring strut. When Eden Hazard left the pitch after 18 minutes Blanc was first to offer him a consolatory handshake. He even gave André Schürrle a paternal pat as he ran on in Hazard's place. Two goals up, two thirds of the tie gone. Blanc was winning this.

The change in his manner by the end was striking. As Chelsea began to drive PSG back with a well-practised switch to accurate, muscular, direct football Blanc seemed to slump. At one point he rubbed furiously at his temples with both hands. He made changes, waving his players on energetically, but none that made any real difference to the game's altered momentum. By the time Mourinho made his dash down the touchline to the corner flag there was no need to dodge his fellow manager. Blanc had sat down; or rather been sat down.

Afterwards PSG's manager seemed unusually meek; not just disappointed but with the chastened air of a managerial Salieri who has just spent the last two hours plonking gamely at his chords while next to him some traumatically gifted improviser tinkles away with terrifying alacrity. There has already been a great deal of praise for Mourinho's role in Chelsea's victory, his success in bundling a depleted team past lavishly appointed and gratingly over-confident A-list opponents.

If football is a combination of tactics and emotion, then Mourinho got both right. He made his plan. And he made up a story to go with it, the well-pitched motivational underdog schtick that dovetailed perfectly with tactics designed to expose PSG's most accessible weakness, discomfort in the face of relentless muscular pressure at the heart of their defence. This was both a tactical success and a coup de théâtre, not to mention a first notch on the all-time Mourinho hit list in his Chelsea 2.0 period, an Elvis in Vegas moment for a well-worn favourite now into his middle years.

For all the emotion of the moment, though, what really stood out was the sense of meticulous planning behind Chelsea's victory. "We worked a lot all week on scenarios – one-nil, two-nil, three-one," Terry said at the final whistle. "For every scenario, we had a gameplan and once again we got it right."

And this really is Mourinho's defining quality on these occasions. His habit of staging practice matches to replicate having men sent off or chasing a game is well documented. To see such thoroughness in action at this level, Mourinho changing the course of the game with his best player injured and powerful opponents already in control, was fascinating. It may even have been salutary for those competing Premier League managers who seem to come out match after match with a single tactical plan in mind, where Mourinho has two or three contingencies lurking in his back pocket.

In the event Chelsea's tactics were basic but effective: from about the 25-minute mark they began to pass the ball longer from midfield and full-back. Initially this was a response to Schürrle's willingness to use his speed cutting in behind the right side of PSG's defence. By the end, with three centre-forwards on the pitch, it had become outright, well-executed direct football. Chelsea were robust too, committing 18 fouls to PSG's 11 as the champions of France shrivelled a little, making just 129 passes in the second half and wasting a succession of chances on the break.

In the process Mourinho turned weaknesses into strengths. A midfield that looked underpowered in the absence of Ramires and Nemanja Matic became at times a shuttle service, David Luiz and Frank Lampard making 21 long passes between them.

Strikers Mourinho feels lack the highest qualities were allowed to use the ones they do have. Demba Ba can batter with the best of them. The loss of Hazard, which might have been a catastrophe, became an opportunity for Schürrle to use his speed and energy, while in the second half Chelsea's left wing was effectively abandoned altogether as César Azpilicueta made nine long passes from that side, more than anyone in the PSG team bar the goalkeeper.

On top of which there was a striking sense of togetherness about Chelsea's players that grew from a slow start. Schürrle was again a key player in this. The German has an endearing public relationship with Mourinho, who seems to treat him a little bit like a promising, coltish young horse. Chelsea's manager refers to him in a sightly offhand way as simply "Schürrle". On Tuesday he ordered the German to warm up with a furious wave of the arm, and ordered him back in with another. Schürrle in return seems utterly willing, chasteningly professional, a player intent on drawing the most out of himself.

As Chelsea did on the night. This match was in many ways made for Mourinho, who has always seemed most comfortable in a very distinct niche among the tiers of elite level football. Give the Portuguese a side who will do exactly as he says, and there is no better manager for inspiring a very good team to beat an exceptional one. This is the best of Mourinho: one level below the very top, an underdog among the overdogs, as he was again at 3-1 down to PSG.

His best achievements, the European Cup wins with Porto and Internazionale, Chelsea's first Premier League title, have followed this pattern, just as Mourinho at Real Madrid never quite seemed the ideal fit.

By contrast with Blanc, Mourinho was laughably at ease talking to the press after making the semi-finals. Asked if this was one of his finest nights in football Mourinho shrugged theatrically, curled his lip and made a dismissive kind of "Pffffffffftt …" noise. There are no easy draws in the semi-finals but Chelsea will fear no one.